Generally, in the production of nano-powder using plasma, two representative extraction methods have been employed. The first method extracts the nano-powder using a filter, and the second method extracts the nano-powder by scraping the nano-powder attached to the walls of a cryogenic container.
The conventional methods as stated above, however, have a problem that it is unable to separate the nano-powder according to particle size thereof.
Another shortcoming of the conventional methods is that only non-reactive oxide-based materials (for example, alumina and so on) are applicable due to a hazard inherent in explosive reaction between colliding nano-powder particles.